In the past, a variety of orthotic devices have been developed for supporting an injury to a bodily joint during the rehabilitation process. The present invention will be described in relation to an orthotic device for supporting the ankle joint, although the invention is applicable to orthotic devices for supporting other bodily joints.
There are various types of orthoses that permit limited ambulation of a patient during treatment of injuries such as fractures or ankle sprains or other injuries to the ankle joint. Severe ankle injuries such as an ankle fracture are normally treated by holding the foot and ankle immobilized in a rigid cast during the initial period of rehabilitation. A cast is uncomfortable because it is heavy and is not removable during its long period of use. It also limits the mobility of the patient.
After the cast is removed, a special light weight brace can be worn to increase patient mobility, while providing the necessary support to prevent twisting or other undue stress on the injured joint. These light weight orthotic devices can permit limited rotational motion of the ankle while the brace is worn. This provides a substantial benefit to the patient during the healing process when compared with a fixed cast. One orthotic device of this type is the tibia/ankle orthosis disclosed in U.S. Pat. No. 4,587,962.
Another type of brace used during the rehabilitation process is an ankle fracture walker disclosed in U.S. Pat. No. 4,771,768. The walker allows a controlled angular range of ankle motion in dorsiflexion and plantar flexion during weight-bearing on the ankle joint, while the ankle joint is supported by the walker, and while the patient walks at a normal walking gait controlled by the walker. As a result, the ankle fracture walker greatly enlarges the methods of treatment of ankle fractures during the rehabilitation process. Ankle fracture walkers normally include a rigid shell that fits around and under the foot, with a curved sole on the bottom of the shell to permit a rocking heel-to-toe motion of the foot during use. In the controlled motion walker, the rocker attaches to the leg of the patient by rigid or semi-rigid uprights extending along the lateral and medial sides of the leg above the ankle joint. The uprights attach to doubleaction ankle joints having rigid support bars that extend upwardly from both sides of a rigid plate on the base of the rocker. The plate is fastened to the rocker by screws. The double-action joint can be adjusted throughout the rehabilitation process to allow maximum mobility of the ankle joint during weight-bearing, depending upon the type of injury involved and the patient's progress during healing. Rehabilitation is functionally better for the patient and total rehabilitation time is reduced when compared with patients using prior art fixed-angle walkers.
A further type of orthotic device disclosed in U.S. Pat. No. 4,517,968 is used for treating ankle sprains. This device can be used for many sports injuries, such as ankle sprains that are not placed in a cast. This device immobilizes the injured joint by use of flexible lateral and medial support members extending along opposite sides of the injured joint. A foot support pivots about a fixed axis for hinging the lateral and medial support members to the foot base. With the user's foot in the foot supporting base, and the support members extending along the lateral and medial sides of the leg, a bandage can be wrapped tightly around the support members above the ankle joint. This immobilizes the ankle joint against lateral and medial movement, while providing limited resistance against torsion, and while also allowing forward and backward rotation about the ankle joint.
The '768, '962 and '968 patents described above are each owned by United States Manufacturing Company, the assignee of this application.
The present invention recognizes a need for a light weight ankle-foot orthosis that can effectively immobilize the ankle joint against lateral and medial movement, while providing a level of resistance against torsion, and also while allowing an adjustable range of motion in dorsiflexion and plantar flexion. There is also a need for uniformly distributing the pressure around the ankle joint, ensuring uniform fit and comfort of the orthosis, and providing a means for effectively making range of motion changes in a reliable light weight orthosis.